Possible Subclinical Leaflet Thrombosis in Bioprosthetic Aortic Valves

To the Editor: Makkar et al. (Nov. 19 issue)(1) report possible subclinical leaflet thrombosis in up to 40% of patients involved in a clinical trial of transcatheter aortic-valve replacement (TAVR). In contrast, we found a relatively low incidence (7%) of possible subclinical valve leaflet thrombosis among patients in our series in which 255 patients underwent TAVR with the use of a CoreValve prosthesis. A retrospective review of our series (unpublished data) showed that in 104 patients, cardiac computed tomography (CT) at a median of 7 days after implantation (range, 3 to 87) (in 51 patients), transesophageal echocardiography at a median . . 

Boni libri or scartafacia? An Inventory of the Commentaries on the ‘Sentences’ as a Mirror of Theological Education at the Dominican Studium at Bologna (14th c.)

After drawing a map of all the commentaries on the ‘Sentences’, preserved in the monumental domus pro libraria of St. Dominic’s Convent of Bologna in the 14th century, the present paper focuses on two particular case studies: the manuscripts A 913 (Bologna, Archiginnasio Library) and A 986 (Bologna, Archiginnasio Library). The analysis will provide an explanatory illustration of how the convent is actively and directly involved in several theological and philosophical discussions characterizing the Parisian milieu in the first decades of the 14th century. Then, the library does not only reflect the geographical diffusion of texts, but also the concrete influence of some doctrines on the late medieval educational activity

Italian Firms in History: Size, Technology and Entrepreneurship

The economic performance of a country depends, among other things, on the strategies and structures of its firms. In the framework that is designed by institutions and policies and determined by technology and macroeconomic cycles, entrepreneurs decide how to allocate available resources in order to face off competitors and to hook up with demand cycles. This paper looks at the evolution of the Italian economy across the last 150 years from a business history perspective. Analyzing Italian firms over the long-term cycles of the global economy and with respect to the different paradigms of the three industrial revolutions, we identify some structural features that explain successes and failures of the Italian economy. In doing this we explicitly connect the micro level of the business enterprise to the macro one of the national business system and explain the comparatively good performance of the Italian economy from the end of the 19th century to the 1970s. Over the last three decades this performance has turned negative, highlighting the role played by the small average size of firms and the failure of institutions to provide incentives for growth.firm size, technological paradigms, innovation, entrepreneurship

Il nuovo Museo Diocesano nell'ex Convento di Sant'Agostino di Piombino: elaborati preliminari ed aspetti illuminotecnici

Oggetto della presente tesi è il recupero edilizio e funzionale dell'ex convento di Sant'Agostino di Piombino (Li). Dopo l'analisi delle vicende storiche e costruttive viene proposta un'ipotesi progettuale per adibire gli immobili a sede di un museo diocesano, attraverso lo strumento del Documento preliminare all'avvio della progettazione. Infine viene sviluppato il progetto illuminotecnico per l'illuminazione delle opere e degli spazi espositivi

Analysis and optimal control theory for a phase field model of Caginalp type with thermal memory

A nonlinear extension of the Caginalp phase field system is considered that takes thermal memory into account. The resulting model, which is a first-order approximation of a thermodynamically consistent system, is inspired by the theories developed by Green and Naghdi. Two equations, resulting from phase dynamics and the universal balance law for internal energy, are written in terms of the phase variable (representing a non-conserved order parameter) and the so-called thermal displacement, i.e., a primitive with respect to time of temperature. Existence and continuous dependence results are shown for weak and strong solutions to the corresponding initial-boundary value problem. Then, an optimal control problem is investigated for a suitable cost functional, in which two data act as controls, namely, the distributed heat source and the initial temperature. Fréchet differentiability between suitable Banach spaces is shown for the control-to-state operator, and meaningful first-order necessary optimality conditions are derived in terms of variational inequalities involving the adjoint variables. Eventually, characterizations of the optimal controls are given

Optimal control of a phase field system modelling tumor growth with chemotaxis and singular potentials

A distributed optimal control problem for an extended model of phase field type for tumor growth is addressed. In this model, the chemotaxis effects are also taken into account. The control is realized by two control variables that design the dispensation of some drugs to the patient. The cost functional is of tracking type, whereas the potential setting has been kept quite general in order to allow regular and singular potentials to be considered. In this direction, some relaxation terms have been introduced in the system. We show the well-posedness of the state system, the Fréchet differentiability of the control-to-state operator in a suitable functional analytic framework, and, lastly, we characterize the first-order necessary conditions of optimality in terms of a variational inequality involving the adjoint variables

Second-order analysis of an optimal control problem in a phase field tumor growth model with singular potentials and chemotaxis

This paper concerns a distributed optimal control problem for a tumor growth model of Cahn-Hilliard type including chemotaxis with possibly singular potentials, where the control and state variables are nonlinearly coupled. First, we discuss the weak well-posedness of the system under very general assumptions for the potentials, which may be singular and nonsmooth. Then, we establish the strong well-posedness of the system in a reduced setting, which however admits the logarithmic potential: this analysis will lay the foundation for the study of the corresponding optimal control problem. Concerning the optimization problem, we address the existence of minimizers and establish both first-order necessary and second-order sufficient conditions for optimality. The mathematically challenging second-order analysis is completely performed here, after showing that the solution mapping is twice continuously differentiable between suitable Banach spaces via the implicit function theorem. Then, we completely identify the second-order Fr\'echet derivative of the control-to-state operator and carry out a thorough and detailed investigation about the related properties.Comment: 52 pages. Keywords: optimal control, tumor growth models, singular potentials, optimality conditions, second-order analysi